lib: add webstreams to Duplex.from()

Refs: https://github.com/nodejs/node/pull/39519
PR-URL: https://github.com/nodejs/node/pull/46190
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Robert Nagy <ronagy@icloud.com>

lib/internal/streams/duplexify.js

@@ -20,6 +20,7 @@ const {
 const { destroyer } = require('internal/streams/destroy');
 const Duplex = require('internal/streams/duplex');
 const Readable = require('internal/streams/readable');
+const Writable = require('internal/streams/writable');
 const { createDeferredPromise } = require('internal/util');
 const from = require('internal/streams/from');
 
@@ -32,6 +33,16 @@ const {
   FunctionPrototypeCall
 } = primordials;
 
+
+const {
+  isBrandCheck,
+} = require('internal/webstreams/util');
+
+const isReadableStream =
+  isBrandCheck('ReadableStream');
+const isWritableStream =
+  isBrandCheck('WritableStream');
+
 // This is needed for pre node 17.
 class Duplexify extends Duplex {
   constructor(options) {
@@ -71,15 +82,13 @@ module.exports = function duplexify(body, name) {
     return _duplexify({ writable: false, readable: false });
   }
 
-  // TODO: Webstreams
-  // if (isReadableStream(body)) {
-  //   return _duplexify({ readable: Readable.fromWeb(body) });
-  // }
+  if (isReadableStream(body)) {
+    return _duplexify({ readable: Readable.fromWeb(body) });
+  }
 
-  // TODO: Webstreams
-  // if (isWritableStream(body)) {
-  //   return _duplexify({ writable: Writable.fromWeb(body) });
-  // }
+  if (isWritableStream(body)) {
+    return _duplexify({ writable: Writable.fromWeb(body) });
+  }
 
   if (typeof body === 'function') {
     const { value, write, final, destroy } = fromAsyncGen(body);
@@ -146,13 +155,12 @@ module.exports = function duplexify(body, name) {
     });
   }
 
-  // TODO: Webstreams.
-  // if (
-  //   isReadableStream(body?.readable) &&
-  //   isWritableStream(body?.writable)
-  // ) {
-  //   return Duplexify.fromWeb(body);
-  // }
+  if (
+    isReadableStream(body?.readable) &&
+    isWritableStream(body?.writable)
+  ) {
+    return Duplexify.fromWeb(body);
+  }
 
   if (
     typeof body?.writable === 'object' ||

test/parallel/test-stream-duplex-from.js

@@ -3,6 +3,7 @@
 const common = require('../common');
 const assert = require('assert');
 const { Duplex, Readable, Writable, pipeline, PassThrough } = require('stream');
+const { ReadableStream, WritableStream } = require('stream/web');
 const { Blob } = require('buffer');
 
 {
@@ -299,3 +300,104 @@ const { Blob } = require('buffer');
     assert.strictEqual(res, 'foobar');
   })).on('close', common.mustCall());
 }
+
+function makeATestReadableStream(value) {
+  return new ReadableStream({
+    start(controller) {
+      controller.enqueue(value);
+      controller.close();
+    }
+  });
+}
+
+function makeATestWritableStream(writeFunc) {
+  return new WritableStream({
+    write(chunk) {
+      writeFunc(chunk);
+    }
+  });
+}
+
+{
+  const d = Duplex.from({
+    readable: makeATestReadableStream('foo'),
+  });
+  assert.strictEqual(d.readable, true);
+  assert.strictEqual(d.writable, false);
+
+  d.on('data', common.mustCall((data) => {
+    assert.strictEqual(data.toString(), 'foo');
+  }));
+
+  d.on('end', common.mustCall(() => {
+    assert.strictEqual(d.readable, false);
+  }));
+}
+
+{
+  const d = Duplex.from(makeATestReadableStream('foo'));
+
+  assert.strictEqual(d.readable, true);
+  assert.strictEqual(d.writable, false);
+
+  d.on('data', common.mustCall((data) => {
+    assert.strictEqual(data.toString(), 'foo');
+  }));
+
+  d.on('end', common.mustCall(() => {
+    assert.strictEqual(d.readable, false);
+  }));
+}
+
+{
+  let ret = '';
+  const d = Duplex.from({
+    writable: makeATestWritableStream((chunk) => ret += chunk),
+  });
+
+  assert.strictEqual(d.readable, false);
+  assert.strictEqual(d.writable, true);
+
+  d.end('foo');
+  d.on('finish', common.mustCall(() => {
+    assert.strictEqual(ret, 'foo');
+    assert.strictEqual(d.writable, false);
+  }));
+}
+
+{
+  let ret = '';
+  const d = Duplex.from(makeATestWritableStream((chunk) => ret += chunk));
+
+  assert.strictEqual(d.readable, false);
+  assert.strictEqual(d.writable, true);
+
+  d.end('foo');
+  d.on('finish', common.mustCall(() => {
+    assert.strictEqual(ret, 'foo');
+    assert.strictEqual(d.writable, false);
+  }));
+}
+
+{
+  let ret = '';
+  const d = Duplex.from({
+    readable: makeATestReadableStream('foo'),
+    writable: makeATestWritableStream((chunk) => ret += chunk),
+  });
+
+  d.end('bar');
+
+  d.on('data', common.mustCall((data) => {
+    assert.strictEqual(data.toString(), 'foo');
+  }));
+
+  d.on('end', common.mustCall(() => {
+    assert.strictEqual(d.readable, false);
+  }));
+
+  d.on('finish', common.mustCall(() => {
+    assert.strictEqual(ret, 'bar');
+    assert.strictEqual(d.writable, false);
+  }));
+}